The problem with TLD-less system is that we already have mismatches of site names with different TLDs. Facebook is great a example of one that would work. But let's say you have callmevlad.com and I have callmevlad.net. With the TLD-less system, who gets the traffic when someone puts "callmevlad" in the Awesome Bar? All those conflicts would need to be resolved before this would work. Maybe it should have been that way from the start but I think it is too late to make that kind of switch. You can't get poop back into a horse without making a big mess.